2-styrylbenzoxazole brighteners



FIP8309 )tR EzlZUsEiZG I I 3,120,520

Patented Feb. 4, 1964 l; 2 3 120 520 is either amino or hydrogen,depending on the value of Z-STYRYLBENZOXAZOLE BRIGHTENERS X m thereduced Precursmt. Bennett G. Buell, Somerville, N.J., assignor toAmerican Cyanamid Company, New York, N.Y., a corporation of Maine 5 Y N0Drawing. Filed Nov. 17, 1961, Ser. No. 153,197 Y 6 Claims. (Cl. 260240)OH This invention relates to the provision of new and useful X X organiccompounds. More particularly, this invention re- NH: 0 lates to theprovision of a new class of fluorescent sub- 10 Y stituted2-styrylbenzoxazole compounds which are use- Y ful inter .alia, forinvisible marking and as brightening zeaminopheflols am yl l rides (III)agents for polymeric organic materials such as natural and syntheticfibers, resin masses and lacquers. J'acylation The compounds of thepresent invent-ion are represented reaction by the following formula:

wherein the R radicals are individually halogen, hydroxy, lower alkoxy,amino, mono-lower alkylamino, di-lower alky-lamino, mercapto, loweralkylthio, arylthio, hydroxy- H n I i p n i O i Y alkylarmno,bls-hydroxyalkylammo or arylamino, mclud- X ing haloandsulfo-substituted derivatives thereof; each NH Q CH=CH X Y radical iseither hydrogen, lower alkoxy, halogen or Y 0 lower alkyl; and n and pare integers each less than two such that their sum is a positiveinteger less than three. The terms lower alkyl and lower alkoxy and thelike mm 2 mmmmmhemls (IV) are used in their conventional sense todesignate cyclic, lgg gzg g straight or branched chain moieties havingfrom one to seven carbon atoms. 40 Y Y Fluorescent compounds which areessentially colorless 0\ have been used for many purposes. Thus theyhave been CH=CH employed for invisibly marking a variety of materials. XMarked materials are not visibly altered, however they N can be readilyidentified by irradiation with ultraviolet Y light. Examples of suchuses are marking inks for laun- Y dry, incorporation in plastics, oil,waxes, etc. By far the yl les major use of fluorescent compounds hasbeen for imparting a bleached, Le, a whiter or brighter, appearance tomaterials which normally have a dull, yellowish tinge in the untreatedstate. Undoubtedly, this optical bleaching action is the result of anability to convert certain ultraviolet components of incident daylightto visible blue components which complement and cancel the undesiredtinge in the untreated material.

The compounds of this invention represented by Formula I, arefluorescent, and have aflinity for, and solubility in, a variety ofmaterials. They can thus be used for invisible marking or opticalbrightening purposes as above l s qidescribed. triazlnylation Thecompounds of this invention may be prepared by a COMPOUNDS 0F FORMULA Iprocess which is represented in the following flow sheet The reaction ofthe aminophenol and the cinnamoyl wherein n, p, R and Y are ashereinbefore defined, X is halide to give the nitro cinnamamidophenolsof Formula either hydrogen or nitro, at least one being nitro, and X IVis preferably conducted in the presence of an organic l reductionamino-2-styrylbenzoxazoles (VI) base as solvent and acid acceptor (e.g.,pyridine, tr iethylamine and dimethylaniline) at elevated temperature.While the above reactionhas been illustrated with an acyl chloride, theacy1 bromide can be used, although the former is preferred for itsconvenience and availability. Since the ultimate compounds of thisinvention may have a triaziny'la-mino group on the benzo moiety of thebenzoxazole and/or the phenyl radical of the styryl moiety, theforegoing reaction may employ aminophenols and cinnamoyl chlorides withor without nitro radicals, provided that at least one reactant has anitro group.

The list of suitable phenols includes inter alia:

2-aminophenol 3-ch-loro-2-aminophenol 4-chloro-2-aminophenolS-chloro-Z-aminophenol 6-chloro-2-aminophenol 3-bromo-2-aminopheno13-fluoro-2-aminophenol 3,6-diohloro-2aaminophenol4,6-dichloro-2aaminophenol 3- bromo-6-chloro-2-aminopheno13-methyl-2aminophenol 4 methyl-2-aminophenol 4-ethyl-2aaminophenol4,6-dimethyl-Z-aminophenol 6-chloro-3 -methyl-2-arninopheno16-chloro-4-methyl-2-aminophenol 3-chloro-6-methyl-2-aminophenol3-bromo-6-methyl-2-aminophenol 4-methoxy-2-aminophenolS-ethoxy-Z-aminophenol 4-met-hoxy-6-chloro Z-aminophenol6-methoxy-4-methyl-2-aminophenol 4-nitro-2-aminophenol 5-nitro-2-aminophenol 5-nitro 4-methyl-2-aminophenol4-nitro-6-methyl-2-aminophenol S-nitro-3-methyl-2-aminophenol5-nitro-3-ethyl-2-arninophenol 5-nitro-4-ethyl-2-aminophenol4-nitro-6-chloro-2-aminophenol 5-nitro-3-chloro-2-aminophenol5-nitro4-chloro-2-aminophenol 5-nitro-4,6-dichloro-2-aminophenol4-nitro-3-chloro6-methyl-2-aminophenol S-nitro-4-methoxy-2-aminophenol4-nitro-6-methoxy-2-aminophenol The list of suitable cinnamoyl halidesincludes inter alia:

Cinnamoyl chloride Cinnamoyl bromide 2,3 or 4-methylcinnamoyl chloride3-ethylcinnamoyl chloride 4-isopropylcinnamoyl chloride2-n-butylcinnamoyl chloride 2-hexylcinnamoyl chloride2,4-dimethylcinnamoyl chloride 2,3 or 4-chlorocinnamoyl chloride 2,3 or4-bromocinnamoyl chloride 3,5-dichlorocinnamoyl chloride2-methyl-4-chlorocinnamoyl chloride 2,3 or 4-methoxycinnamoyl chloride3-methoxy-4-chlorocinnamoyl chloride 6-methoxy-4-methylcinnamoylchloride 4-nitrocinnamoyl chloride 4-nitrocinnamoyl bromide2-methyl-4-nitrocinnamoyl chloride 3-methyl-4-nitrocinnamoyl chloride 3-chloro-4-nitrocinnamoyl chloride 3,5 dichloro-4-nitrocinnamoyl chlorideZ-methyl-S-chloro-4-nitrocinnamoyl chloride 2-methoxy-4-nitrocinnamoylchloride 3-methoxy-6-chloro-4-nitrocinnamoyl chloride Thenitro-Z-cinnamamidophenols of Formula IV prepared by the foregoingreaction are ring-closed by a conventional dehydration reaction to yieldthe corresponding nitro-2-styrylbenzoxazoles of Formula V. Suchdehydration may be effected by fusion in a non-aqueous medium such asboric acid at a temperature above C., but below decomposition, i.e., 275C.

The resulting nitro-2-styrylbenzoxazoles of Formula V are reduced totheir amino analogs of Formula VI by treatment with conventionalreducing agents such as inorganic sulfides, e.g., hydrogen sulfide,sodium sulfide and sodium hydrosulfide, in an organic solvent such as alower alkanol.

The compounds of Formula I are obtained by reacting the free aminogroups of the compounds of Formula VI with a chlorotriazine derivativealong conventional lines. Thus, the amino-2-styrylbenzoxazole may bereacted with 2-chlorotriazinyl compounds to give the product. Oralternatively, the amino-2-styrylbenzoxazole is reacted with one mole ofcyanuric chloride, and the remaining chlorines replaced if desired byfurther reaction with water, alcohols, phenols, ammonia, primary andsecondary amines, bisulfide salts, mercaptans or thiophenols.

Suitable triazines for this reaction are inter alia:

Cyanuric chloride Cyanuric bromide 2,6-dichloro-4-methoxy-s-triazine4,6-dimethoxy-Z-chloro-s-triazine 4,6-diethoxy-2-chloro-s-triazine4,6-bisfi-ethoxyethoxy) -2-chloro-s-triazine2,6-dichloro-4-hydroxy-s-triazine 2-chloro-4,6-dihydroxy-s-triazine2-chloro-4,6-diamino-s-triaziue 4-amino-2,6-dichloro-s-triazine2-chloro-4,6-bis dimethylamino -s-triazine2,6-dichloro-4-methylamino-s-triaZine 2-chloro-4,6-bis (hydroxyethylamino-s-triazine 2,6-dichloro-4-hydroxyethylamino-s-triazine2,6-dichloro-4-anilino-s-triazine 2,6-dichloro-4- (p-sulfoanilino)-s-triazine When halogen atoms still remain on the triazine ring of thetriazinylamino-2-styrylbenzoxazole thus formed, these may be furtherreplaced by reaction with nucleophilic agents, such as Water, a loweralkanol (e.g., methyl alcohol and ethyl alcohol), alkyl glycol ethers(e.g., methoxyethanol), phenol, ammonia, lower alkylamines (e.g.,ethylamine and dimethylamine), lower alkanol amines (e.g.,monoethanolamine, diethanolamine and isopropanolamine), aniline,sulfanilic acid, metanilic acid, sodium bisulfide, lower alkylmercaptans (e.g., methyl mercaptan) or thiophenol.

The following examples in which parts are by weight, are presented tofurther illustrate this invention.

Example 1 To a solution of 15.4 grams of Z-amino-S-nitrophenol in 30 ml.of pyridine is added 16.7 grams of cinnamoyl chloride. The mixture isheated on a steam bath until the reaction is complete 0/: hour), cooledand poured into an ice-water mixture. The product is isolated byfiltration and dried at 55 C.

Example 2 OH NH(||JOH=CHNO2 To a solution of 21 grams of4-nitrocinnamoyl chloride in 50 ml. of pyridine is added 10.9 grams ofo-aminophenol in 100 ml. of pyridine. The solution is heated at refluxfor two hours, drowned in water, filtered and dried at 55 C.

Example 3 N02- OH A mixture of 9.65 grams of 4-nitrocinnamic acid and100 ml. of thionyl chloride is heated at reflux until the formation ofthe acid chloride is complete (2 hrs.). A clear solution results. Theexcess thionyl chloride is removed by vacuum distillation, benzene addedand the distillation continued to remove traces of thionyl chloride andthe benzene. The residue is dissolved in 50 ml. of pyridine and 7.2grams of 5-nitro-2-aminophenol added. The mixture is heated at refluxuntil the reaction is complete (2 hrs), and is drowned in an ice-watermixture. The amide is isolated by filtration and dried.

Example 4 Heated on a steam bath are 22.5 grams of 2-amino-4nitrophenol, 150 ml. of pyridine and 24.3 grams of cinnamoyl chloride.When the reaction is complete, the mixture is poured into ice Water. Theresultant product, 2- cinnamamido-4-nitrophenol is isolated byfiltration, washed with water and dried at 55 C.

Example 5 Example 6 The above product is obtained by following theprocedure of Example 3, with the substitution of equivalent amounts of4-chloro-5'-nitro-2-aminophenol for the 5-nitro-2-aminophenol, and of3-methyl-4-nitrocinnamic acid for the 4-ni-trocinnamic acid of thatexample.

Example 7 OaN- /OTOH=OH A mixture of 27. 1 grams ofZ-cinnamamido-S-nitrophenol and 612 grams of boric acid is fused at 240C. until the reaction is complete. The fusion product is ground, takenup to hot methoxyethanol, treated with activated charcoal and filtered.The filtrate is cooled and the product precipitated by the addition ofwater. The

product, 2-styryl-6-nitrobenzoxazole, is isolated by filtration, washedwith water and dried at 55 C.

Example 8 TOH=C 11- N02 The amide of Example 2 is fused with 6 grams ofboric acid at 235240 C. for 15 minutes. The fusion mixture is dissolvedin methoxyethanol, clarified with activated charcoal, filtered andreprecipitated by the addition of water to yield the product.

Example 9 0 N02 Taken-{34x02 The above product is obtained by fusion ofthe compound of Example 3 in accordance with the procedure of Example 8.

Example 10 The above product is obtained by fusion of the amide ofExample 4 in accordance with the procedure of Example 8. 1

Example 11 The above product is obtained by fusion of the amide ofExample 5 in accordance with the procedure of Example 8.

Example 12 l 01- N CH3 The above product is obtained by fusion of theproduct of Example 6 in accordance with the procedure of Example 8.

Example 13 0 11m Ton=on Example 14 The nitrobenzoxazole of Example 8 isreduced in 5'00 ml. of alcohol at C. by addition of 32 grams of sodiumhydrosulfide in 200 ml. of water. When the reaction is complete,activated charcoal is added and the mixture filtered and then drowned.Filtnation, washing and drying yields the product.

Example 15 TCH=CH-NH2 N The nit-robenzoxa zole of Example 9 is reducedby slurrying in 200 ml. of alcohol, adding 16 grams of NaSI-I in 50 ml.of water and heating at reflux until the reaction is complete (1 hr.).The product is obtained by drowning on ice, filtration and drying.

Example 16 Example 17 O r -Q NH -N (502135 Following the reductionprocedure of Example 13 the product of Example -11 is converted to thecompound of the above formula.

Example 1 8 Following the reduction procedure of Example 13 thebenzox-azole of Example 12 is converted to the compound of the aboveformula.

The following examples show the preparation of the final compounds ofthis invention from the intermediates obtained in the foregoingexamples. The evaluation of the compounds as brighteners is based inpart on results of the following test procedures.

A. METHOD OF APPLYING BRIGHTNESS 'ro COTTON,

vNYLON AND ACETATE IN THE PRESENCE OF DE- TERGENT To 40 cc. of distilledwater in a Laimder-Ometer jar is added 10 cc. of a 0.005% concentrationof the br-ightener product in water and 50 cc. of a 1.0% concentrationof detergent in water. or piece of fabric comprising bleached cottonmuslin 80 x 80, or resin treated cotton or scoured nylon tricot, isadded. The jar is closed, shaken and run for 25 minutes at 130 F. in aLaunder-Ometer. The fabric is then rinsed three times with water at 7 F.and air dried in the dark at 75 F. and 65% relative humidity.

Detergents used may 'be 'nonionic or anionic.

B. METHOD FOR APPLYING BRIGHTNESS TO WOOL AND NYLON IN THE PRESENCE OFACID OF GLAUBERS SALT.

To a Launder-Ometer jar is added 98.5 cc. or 97.5 cc. of distilledwater, depending on the respective choice of the following acids.

1.5 cc. oi a solution of 28% acetic acid 2.5 cc. of a 10% solution ofGlaubers salt Then 5 cc. of 0.005% solution of brightener is addedfollowed by a S-grarn skein or piece of nylon or wet-out wool flannel.The 'jar is closed and run for 25 minutes A wet-out five-gram skeinacetate.

OOHa

A mixture of 2.36 grams of the compound of Example 13, 150 ml. ofme-thoxyethanol, 1.93 grams out 2-chloro- 4,6-dimethoxy-s-triazine and0.84 gram of sodium bicarbonate is stirred and heated until thetemperature reaches 97 C. The reaction mixture is maintained at thistemperature until the reaction is complete. It is then cooled and 200ml. water added. The product is filtered and air dried.

This :brightener, when applied to cotton and nylon, significantlywhitens the cloth. The strength and intensity of fluorescence inultraviolet light is 150 to 200% greater than an equivalent amount of aprior art commercial stilbene brightener on cotton. On nylon it is 200%stronger than the equivalent amount of a commercial coumarin brightener.Further, the l-ightfastness of the treated fabric is likewise greatlysuperior.

This brightener also whitens acetate and wool, resintreated cotton, andto some extent terephthalic polyester fiber. It builds up well on cottonin successive detergent washes, can be applied to cotton from a cationicsottener bath, and in general is a preferred brightener for cotton.

Example 20 OCH3 A mixture or 4.72 grams of the product of Example 13,150 ml. of acetone and 3.96 grams of 2,4-dichloro- 6- methoxy-s-triazineis stirred and heated gradually to 44 C. It is then cooled and dilutedwith water. The product is isolated 'by filtration, washed with waterand dried at 55 C.

This brightener markedly whitens cotton, nylon and It shows goodsubstantivity for cotton, resintreated cotton and acetate and especiallygood substantivity for nylon.

Example 21 To ml. of acetone is added 2.36 grams of the product ofExample 13. After cooling to 0 C., 1.86 grams of cyanuric chloride in 50ml. acetone is added. To the resultant slurry is added 2 ml. of 5 Nsodiunr hydroxide solution and after stirring a half hour, the reactionis heated to 50 C., 1.64 grams of sodium bicarbonate and 200 ml. waterare added. The mixture is then cooled and the product filtered anddried. It is then reprecipitated tfirom glacial acetic acid by theaddition of water, filtered and washed with Water. The Wet product isdissolved in a hot solution of methoxyethanol with the aid of 5 N NaOHsolution and water, clarified by filtration through activated charcoaland reprecipitated by the addition of acid. The product is filtered,washed with water and dried.

This brightener shows excellent substantivity for cotton and goodfastness to light.

Example 22 NHOHzOHzOH Two grams of the product of Example 13 in 125 ml.10

01' acetone is cooled to C. To it is added 1.55 grams of cyanuricchloride in 50 ml. of acetone. Then 1.7 ml. of N sodium hydroxidesolution and 25 ml. water are added and the whole stirred one hour.Ethanolamine, 2.05 grams, is added and the reaction mixture heated to 50C. The acetone is distilled off and replaced with methoxyethanol. Themixture is heated at reflux until the reaction is complete. It is thencooled, water is added and the mixture is allowed to stand. The productis isolated by filtration, washed with water and dried at 55 C.

This brightener shows excellent alfinity for, and fluorescence oncotton, nylon, acetate and wool. Also it has good lightfastness.

Example 23 To a mixture of 3.46 grams sul'fanilic acid, 150 grams water,4 ml. 5 N NaOH solution and 100 ml. acetone,

cooled to 0 C., is added 3.68 grams of cyanuric chloride in 100 ofacetone. The temperature is kept 0-5 C. and the pH maintained above 6with 4 ml. 5 N NaOH solution until the reaction is complete.

To the 2,6-dichloro-4-(p-sulfoanilino)-s-triazine thus obtained is added4.72 grams of the product of Example 13 in 150 ml. of acetone. The wholeis heated to 50 C. and stirred until the reaction is complete (2 hrs).It is then allowed to cool to room temperature, filtered, and theproduct washed with acetone, then water, then acetone, and dried at 40C. under vacuum.

This brightener has excellent afiinity for, and fluorescence on, cottonwhen applied in detergent solutions, and on Wool and nylon when appliedin acid solution. It is excellent in its ability to brighten cotton froma laundry acid sour bath.

Example 24 NHOHzOHzOH The procedure of Example 22 is followed exceptthat the product of Example 16 is used instead of the product forExample 13. The product obtained is recrystallized twice fromwater-ethanol mixtures.

This product shows high aflinity and fluorescence on cotton and goodaffinity for nylon. It forms blue fluorescent solutions in organicsolvents such as methoxyethanol, ethanol, dioxan and the like.

Ari INE N(OHaCHaOH)z 1 0 Example 25 C-NH: N I

The procedure of Example 19 is followed except that the product ofExample 14 is used in place of the product of Example 13, and 1.75 g. of2-chloro-4,6-diamino-s-triazine in place of the chlorodimethoxytriazine.The product is a pale yellow solid which has blue fluorescence in dioxansolution, and shows good aflinity and fluorescence on cotton and nylon.

Example 26 l NHCHzCHzOH Two grams of the product of Example 14 isreacted with 1.55 g. of cyanuric chloride by the procedure of Example22. Then 0.78 g. of aniline is added, and the mixture heated at 5 0 C.for one hour. After addition of one gram of ethanolarnine thetemperature of the reaction mixture is gradually raised by distillingoff the acetone and replacing with methoxyethanol, and the mixture isheld at reflux till reaction is complete. After cooling, and addition ofwater, the product is isolated by filtration. It shows a bluefluorescence in dioxan solution.

Example 27 O v N TOH=CHNH| w-NH N l. -N -o1 A mixture of 2.51 g. of theproduct of Example 15 and 3.7 g. of cyanuric chloride in ml. of acetoneis reacted at 0 C. with addition of 3.5 ml. of 5 N caustic in 50 ml. ofwater. After reaction is complete, 2.5 g. of p-chloroaniline is addedand a second reaction allowed to proceed at 50 C. to completion. Then4.2 g. of diethanolamine is added, the acetone removed and replaced bymethoxyethanol, and the mixture heated at reflux till the final reactionis ended. After cooling and dilution with water the product is filteredoff. It is a yellow solid having a strong blue fluorescence in dioxansolution.

Example 28 0 N Tomca- -NH I W-som 2 N N CH3S- NH -N O C2H5 I l N N s -ons-cm A mixture of 3.6 g. of the product of Example 17 and 3.7 g. ofcyanuric chloride is reacted in 150 ml. of acetone at 0 C. with additionof 3.5 ml. of 5 N caustic, until the primary bis-condensation iscomplete. A solution of 3.3 g. of potassium methyl mercaptide in aminimum amount of 1% caustic is added, and the mixture is stirred at 50C. for one hour. Following this, the acetone is removed and replaced bymethoxyethanol, and heating is continued at reflux until the reaction iscomplete. After cooling,

and dilution of the mixture with water, .the product is recovered byfiltration. It gives a blue fluorescent solution in dioxan andmethoxyethanol.

1 1 12 Example 29 N w I N N N N 01- N CH:

N(CH2CH2OH)1 l HOHzCHzOHh Three grams of the product of Example 18 isreacted 3. The compound of the formula with 3.7 g. of cyanuric chloridein acetone to form the pri- N mary bis-condensation product. Then 2.1 g.of diethanol- O1 WNH 0H=OH amine is added, and the secondarycondensation carried I out at 50 C. (about one hour). A solution of 2.5g. of V N thiophenol in a minimum amount of 5% caustic is then added,the acetone replaced by methoxyethanol, and the 00113 final condensationcarried to completion at reflux. Dilu- 4 The compound of the formulation with water and filtration gives the product, which is N orecrystallized from methoxyethanol. It shows blue fluOr- H03S-NH NHescence in this solvent, and also fluoresces on nylon and l acetate. N NN I claim:

1. A compound of the formula 01 wherein each Y radical is a memberselected from the 5. The compound of the formula group consisting ofhydrogen, halogen, lower alkoxy, and /N\ 0 lower alkyl, R isindividually selected from the group con- 'H W U sisting of halogen,hydroxy, lower alkoxy, amino, mono N N lower alkylamino, di loweralkylamino, mercapto, lower V N alkylthio, phenylthio, lowerhydroxyalkylamino, bis-lower hydroxyalkylarnino, lower alkoxyalkoxy,anilino and sul- OH foanilino; and n and p are integers less than twosuch that The compound of the formula their sum is a positive integerless than three.

2. The compound of the formula N N f j CH=OH NHCI-IzCHzOH I I ReferencesCited in the file of this patent Cil Conant et al.: The Chemistry ofOrganic Compounds, 3rd Edition, pages 558 to 560, the Macmillan Co., NewYork (1947), QD 251. C67.

1. A COMPOUND OF THE FORMULA
 2. THE COMPOUND OF THE FORMULA 